1. Field of the Invention
The present invention relates in general to a snap in valve stem constructed to support a structure, and more particularly to a snap in valve stem for use with a tubeless tire capable of supporting a radio transmitter package for a tire pressure monitoring system.
2. Description of the Related Art
While the present invention finds particular utility as a tubeless tire valve stem and will be described with specific reference thereto, it should be understood that the present invention has broader applications and can find utility in any application employing a snap in valve stem or where the valve stem supports some type of a structure or device.
Snap in valve stems for tubeless tires are well known in this art. These valve stems are designed with a rubber body or housing that is inserted through a valve stem opening from inside a tire rim, also referred to as the underside of a tire rim. The rubber body is pulled and stretched at least in part through the valve stem opening and xe2x80x9csnappedxe2x80x9d in place. The rubber is confined within the space of the opening and is compressed peripherally around the valve stem opening to provide an airtight fit. Snap in valve stems have become quite standardized in the tire industry. They need to be capable of being securely mounted upon the rim, being airtight, and remaining airtight when the tire is inflated and in service. Examples of such snap in valve stems are disclosed in U.S. Pat. Nos. 2,818,101, 2,968,333, and 2,995,168.
Recently, there has been a significant amount of interest in proper tire inflation. An under inflated or over inflated tire will cause uneven tread wear and will shorten the useful life of the tire. Underinflated tires are known to cause tread separation and/or blowouts which can lead to serious injury and property damage. Tire pressure monitoring systems are devices that are found in some commercial vehicles or luxury automobiles. These devices alert the vehicle operator when a tire""s pressure falls below or exceeds a desired or predetermined optimum pressure. Some of the components of a tire pressure monitoring system are typically mounted inside the tire rim, like for example, the radio transmitter assembly. A transmitter assembly located in each tire communicates via radio frequency or other means with a command module in the vehicle cab. The command module can use visual or audio signals to alert the operator if one or more of the tires are underinflated or overinflated, and in some cases depending upon the complexity of the system may even take corrective actions or advise a centralized fleet vehicle command center for on the road maintenance. As the costs for tire pressure monitoring systems continue to decline and their popularity increases, there will be a greater demand for these systems for use on all types of vehicles.
The valve stems employed with these tire pressure monitoring systems are a metal clamp-in type or bolt on valve stem, or an equivalent structure, that can support the radio transmitter assembly. These types of valve stems are costly and fairly complex structures. Additionally, they can be time consuming to install.
It has now become desirable to develop a valve stem with a snap in design that is capable of supporting a transmitter assembly of a tire pressure monitoring system within the rim of a tire. The snap in valve stem should have a design that allows for a simple, easy, straightforward process for installation, and yet provide a sturdy, rugged support for the tire pressure monitoring system transmitter.
An object of the present invention is to provide a snap in valve stem adapted for mounting in an opening and supporting a structure therein.
Another object of the present invention is to provide a snap in valve stem for a tubeless tire capable of supporting a radio transmitter assembly of a tire pressure monitoring system.
Another object of the present invention is to provide a snap in valve stem having a two piece insert design that allows one side of the valve stem to flex independently of the other side of the valve stem to facilitate easy mounting within an opening and still support the tire pressure monitoring system transmitter.
The above and other objects of the present invention are accomplished with a snap in valve stem adapted for mounting in an opening and for supporting a structure, comprising a body formed of an elastomeric material and having a longitudinally extending bore therethrough. The body has an upper end portion and a lower end portion. The external diameter of the body increases in diameter towards the lower end portion. The upper end portion has an external diameter constructed to pass through an opening and the lower end portion has a diameter constructed to sealingly interfit within the opening. A first insert is received within the bore of the body at the upper end of the body, and has an outer end extending out from the upper end portion of the body. The outer end of the first insert is constructed to receive a cover. An interior surface of the outer end of the first insert is constructed for receiving a valve core. The first insert includes an inner end that terminates within the lower end portion of the body. A second insert with an inner and outer end is also received within the bore of the body at the lower end portion of the body. The outer end of the second insert extends out from the lower end portion and includes means for supporting a structure.
The two piece insert design in accordance with the present invention allows the body of the valve stem to stretch during insertion in the opening and then compress after insertion for providing a sealing fit.